measuring milliamp current

Discussion in 'General Electronics Chat' started by Avicreats, Jan 18, 2013.

  1. Avicreats

    Thread Starter New Member

    Jan 18, 2013
    19
    0
    I have to measure the current which will be around 1.3miiliamp.
    what i did was used a 80/2 split core ct and inserted the phase wire into hole of ct and increased the number of primary turns into 3,so the flux induced on core was three times the current flow.On secondary i was able to detect the flow of current using a multimeter.the measured value on sec was .0012amps.To find phase current i calculated as ((.0012/3)*40) and the value is .0133amps ie,13.3milliamps which is far differing from 1.3milliamps.
    Is my way of doing is right?
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,021
    3,235
    What is the frequency of the current?

    Do you have 40 turns on the secondary? If so then the theoretical secondary current would be 3/40 of the primary current. The current is reduced by the ratio of primary to secondary turns, not increased.
     
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  3. Avicreats

    Thread Starter New Member

    Jan 18, 2013
    19
    0
    of-course the sec currnt is reduced by turns ratio.And frequency remains unchanged throughout the ct operation, and will it make any difference in sec value?.
    Since the ct is not showing precise value,is there any other components to measure milliamp currents.
     
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